In a device that performs optical communications (optical distributor), a heat generation density is increased in order to respond to market needs for an improvement in performance and a reduction in size, and thus, a heat dissipation structure that dissipates heat of the optical distributor poses a problem.
Accordingly, for example, in a technique disclosed in Patent Document 1, a heat dissipation structure that uses a difference in thermal conductivity between a resin and a metal is mounted to an optical distributor. In this heat dissipation structure, a stem of the optical distributor is sandwiched between heat transfer parts made of the resin from above and below, and the upper and lower heat transfer parts are coupled to each other with a metal frame having a coefficient of thermal expansion lower than those of the stem and the heat transfer parts, whereby expansion of the resin during heat generation is suppressed by the metal frame. Thus, during the heat generation, the stem and the heat transfer parts are brought into tight contact with each other to reduce thermal resistance thereof, and thus, a heat dissipation efficiency thereof is increased.